thai-ty

Too much oil. I'd start at 40:1 with an air cooled iron cylinder liner in an alloy barrel.

Bar the Kawa lime green colour scheme, God that is a good looking motorcycle IMO.

Mainshaft (output shaft) oil seal is shot also. The shaft your sprkt sits on. Sounds like a lot of dried out/aged/incorrectly fitted/poor quality aftermarket seals on the motor.....

Not really. A couple of special tools, good selection of normal quality hand tools, common sense and a shop manual, and your time is your labour. They are not a difficult engine to work on. IMO, a 2T single is one of the easiest motors to rebuild.

That ain't no trials bike dude....

Honda CRF250l trail bike for $2.5-3k. You don't even really need a trial bike.

Concur. Until.... a few years ago when Amal brought out the Premier range for MK I Concentrics, these are superbly made, different materials, hard anodized slide, removable pilot jet (hooray!) and are just top notch kit, certainly better than the stock versions you can still buy. Night & Day. I have to say, Amal have really upped their game in the last decade, all the older models like the 376/389 Monobloc and even older stuff is all being remade and IMO, better quality than ever before.

"Fit and go" are always close generalizations and get you in the ball park. It's very rare a carb conversion kit fuels perfectly in all the stages for most bikes. There's some Mikuni tuning stuff on the net, but they are virtually the same as an Amal. Needle position and needle jet is the meat and potatoes of throttle position, affecting 1/4 - 3/4, just off idle the slide cutaway affects things too. I think you'll get there quickly.

I presume you have read the tuning guide for Amals, which is the same as for Mikunis. Before swapping jets and spending money, i'd have a go at lifting or lowering your needle. By what you have written it is possibly over rich off idle, hence drop the needle by one groove. Main jet is 3/4 - wide open throttle only, you have to get there first via slide cutaway, needle position and needle jet.

..... and breathe.....

The size and weight of the crank would make one think so... the term bulletproof is a perfect fit for the bottom end of this motor.

Had to have a peek to see what the fuss was all about. Jeez, anybody got any Kleenex? Concur, eye watering....?

So, completely different bottom end? Clutch plates? I was always under the impression the TYZ was pretty much a water cooled top end on a TY Mono bottom end. Even the side cases look similar-ish.... Then again, i've never seen one in the flesh nor had a motor on the bench....

This. +1. With ALL THE MODS you listed, i can guarantee you it aint gonna run on stock base settings.

Pedantic, ridiculous and daft.

Cargo trousers/pants, preferably in digital camo. Cheap, comfortable, tough, baggy, lots of pockets, and the camo design hides a multitude of sins....?

+1. Nothing better for getting that new out of the showroom look on crankcases. Nothing. And unlike a 4 stroke, a 2 stroke has not exactly got oil galleries etc in the cases to be wary of when cleaning prior to re-assembly.

The stands in the OP look great, and versatile, but, IMHO, unless you are doing it for a living, 8 hours a day every day, and building different motors, they are a bit over the top. A simple box section stand holding the motor in a normal vertical position is perfectly fine for your own engine, and can be knocked up in half an hour with a saw, grinder and mig welder. Spoiler alert, i've been a m/c mechanic my whole adult life, inc having my own shop for 15 years in the UK specializing in certain engines, we had an individual stand for every motor and separate g/box. Took up a lot of space on the wall and under the benches, the above pic seems like a great 3 in 1 idea....

Concur. Even advertising a Hagon shock for guys with smaller pockets....

the cranks/flywheels are ridiculously heavy in Yamaha 250/350 motors.

.... is the weight difference of the cranks.... ..fixed it for ya....

Pic of your fabricated brake pedal please post plating.

It's either all or nothing with PROPER plating. So your "bit of a frame loop" would have to be detachable. Here's a pic of my '79 830cc T140 with the frame and s/arm bright nickel plated. Pics is from a couple of years ago, polishing and plating was done in 1994.

Cargo pants. Lotsa pockets, nice loose comfy fitting. Preferably in a nice camo look - hides the dirt, saves washing every weekend. Thank me later.

I had a metal finishing shop in the UK for 15 years - Precision Surface Preparation. Metal polishing, all disciplines, and wet and dry bead blasting. The plating itself was farmed out, as was the chemical stripping of old plating, prior to us doing all the prep work. Plating is only as good as the prep work. Labour intensive - it's where most of the money goes. In answer to your questions; # zinc and nickel/chrome plating are very very different processes. # i have no experience with home hobby kits. # I highly doubt you will be able to plate or replate a m/c frame with such a kit. # No, nickel goes on before chrome. Triple chrome plate is polish, copper, polish, nickel, polish, chrome. # Doubtfull, and if you did/could, it will look a mess, see above. Regards, TG.